预制层衬底加热对Cu_2ZnSnS_4薄膜性能的影响

Effect of Substrate Heating on Cu_2ZnSnS_4 Thin Films Properties

本文采用二步法制备Cu_2ZnSnS_4(CZTS)薄膜,首先通过真空热蒸发制备CuZnSn(CZT)预制层,其衬底加热温度分别为20℃、50℃、75℃和100℃,然后对所制备的CZT预制层在400℃下硫化60 min,从而制备出CZTS薄膜。利用XRD、Raman、SEM、反射谱和透射谱对所制备的CZTS薄膜进行了表征,实验结果表明,预制层衬底加热温度对CZTS薄膜结构与光学特性有很大影响,在衬底加热50℃时制备预制层硫化后所得CZTS薄膜具有高的结晶度、致密均匀的薄膜表面和最佳1.5 e V光学带隙。此外,与衬底未加热制备预制层在500℃和90 min最佳硫化条件下所制备的高纯CZTS薄膜相比,在50℃预制层衬底加热条件下所制备CZTS薄膜具有更好地结晶质量、更低的硫化温度和更短的硫化时间,这种现象表明衬底加热制备金属预制层利于更高品质CZTS薄膜的制备,可有效的降低硫化温度和缩短硫化时间,当前的研究结果为在低温下实现高质量CZTS薄膜的制备提供了一种有效的途径。

The Cu2ZnSnS4（ CZTS） thin films were fabricated using the two-step process. Firstly,Cu Zn Sn（ CZT） precursors were deposited by thermal evaporation in vacuum chambers with different substrate temperature,i. e. 20 ℃,50 ℃,75 ℃ and 100 ℃. And then Cu Zn Sn（ CZT） precursors were sulfurized into CZTS thin films at 400 ℃ for 60 min. CZTS thin films were examined by X-ray diffraction（ XRD）, micro-Raman system（ Raman）, scanning electron microscopy（ SEM）, and ultraviolet spectrophotometer（ UV-2550） for transmission and reflection spectra. The results indicate that the substrate temperature of precursor has a great influence on thin film structure and optical properties. The prepared CZTS thin film by sulfurization of metal CZT thin films with 50 ℃ substrate temperature has high crystallinity,compact and smooth surface,and suitable optical properties of 1. 5 e V. Compared with pure CZTS thin film formed by sulfurizing metal CZT thin films without substrate temperature under 500℃ duration 90 min,the prepared CZTS thin film by sulfruizing the fabricated CZT precursors at 50 ℃has better crystal quality,lower sulfurization temperature and shorter sulfurization time. This phenomenonshows that the heating of precursors not only is helpful for the synthesis of CZTS thin films with better crystal quality but also can effectively reduce the sulfurization temperature and shorten the sulfurization time. The present study provides an effective way for the preparation of high quality CZTS thin thin films at low temperature.